Switch having ganged contacts mounted on opposite sides of circuit board

ABSTRACT

A switch apparatus is described including a pair of movable contacts separately mounted on opposite sides of an etched circuit board and ganged together by a loose coupling including a coupling member extending through a hole in such circuit board. Fixed contacts are provided as conductive strips on both sides of the circuit board and the movable contacts are moved in and out of engagement with such fixed contacts by a rotary cam actuator mounted on such circuit board. In one embodiment, a cam follower surface is provided on one of a pair of insulator members joining the movable contacts to mounting springs, while in another embodiment the cam follower surface is provided on one end on the coupling member and such coupling member extends through a hole in the support portion of one of the movable contacts, while its other end engages the support portion of the other movable contact. The movable contacts may be short circuiting contacts each including a pair of spaced leg portions through which current flows in opposite directions to produce opposing fields which reduce the contact inductance.

United States Patent [191 Holland et a1. A

[54] SWITCH HAVING GANGED CONTACTS MOUNTED ON OPPOSITE SIDES OF CIRCUITBOARD [75] Inventors: Kenneth Holland; Anthony E. Sprando, both ofPortland, Oreg.

[73] Assignee: Tektronix, Inc., Beaverton, Oreg. [22] Filed: Feb, 4,1971 211' Appl. No.: 112,583

[52] u.s. Cl. ..200/1s3 LB, 200/6 BB, 200/166 J [51] Int. Cl. ..H0lh3/42, I-IOlh 19/62 [58] Field of Search ..200/l66 PC, 153 LB, 166 J,200/6 BB, 1 TK, 37 A, 30 AA [56] References Cited UNITED STATES PATENTS2,033,005 3/1936 Pinkus ..200/30 AA 2,873,324 2/1959 3,499,128 3/19703,562,464 2/1971 3,193,651 7/1965 3,256,401 6/1966 Dawson ..200/l66 .1 XFOREIGN PATENTS OR APPLICATIONS 929,312 5/1955 Germany ..200/153 LB1,531,565

5/1968 France ..200/153 LB [451 March 6, 1973 Primary Examiner-Herman J.l-Iohauser Assistant Examiner--Robert A. Vanderhye v Attorney-Buckhorn,Blore, Klarquist and Sparkman [5 7] ABSTRACT A switch apparatus isdescribed including a pair of movable contacts separately mounted onopposite sides of an etched circuit board and ganged together by a loosecoupling including a coupling member ex- 7 tending through a hole insuch circuit board. Fixed contacts are provided as conductive strips onboth sides of the circuit board and the movable contacts are moved inand out of engagement with such fixed contacts by a rotary cam actuatormounted on such circuit board. In one embodiment, acam follower surfaceis provided on one of a pair of insulator members joining the movablecontacts to mounting springs, while in another embodiment the camfollower surface is provided on one end on the coupling member and suchcoupling member extends through a hole in the support portion of one ofthe movable contacts, while its other end engages the support portion ofthe other movable contact. The movable contacts may be short circuitingcontacts each including a pair of spaced leg portions through whichcurrent flows in opposite directions to produce opposing fields whichreduce the contact inductance.

17 Claims, 4 Drawing Figures PATENTEDHAR 61975 LLAND SPRANDO INVENTORS.

KENNETH C. HO ANTHONY E.

FIG. 4

BUCKHORN, BLORE, KLARQUIST 8. SPARKMAN ATTORNEYS SWITCII HAVING GANGEDCONTACTS MOUNTED ON OPPOSITE SIDES OF CIRCUIT I BOARD BACKGROUND OF THEINVENTION The subject matter of the present invention relates surfaceprovided on the coupling member or on an ingenerally to electricalswitch apparatus, and in particular, to switch apparatus including apair of ganged movable contacts mounted on the opposite sides of aninsulator plate, such as an etched circuit board, having fixed contactsprovided thereon,--such as conductive strips coated on the circuitboard. The movable contacts are ganged together by a loose couplingincluding a movable coupling member extending through a hole in suchcircuit board. Rotary cam actuating means mounted onone side of thecircuit board may be employed to move the movable contacts by engagementwith a cam follower surface provided either on an insulator memberjoining the movable contact to a mounting spring or on one end of thecoupling member. As a including a coupling member extending through ahole result of the gauging operation of the coupling member, camactuation of onemovable contact toward the circuit board causes theother movable contact to be moved away from the circuit board. In oneembodiment, the movable contact is joined through an insulator member toa mounting spring to insulate such contact which lowers the straycapacitance of such movahis contact.

Previously, in French Pat. No. 1,531,565, it has been proposed toprovide a cam actuated switch in which two movable contacts are providedon opposite sides of a printed circuit board by forming such contactsintegral with a common spring support member fixedly attached at one endto the circuit board and extending through a hole in such circuit board.As a result of not separately mounting-the pair of movable contacts ontwo different mounting springs and ganging them together with a loosecoupling in the manner of the present invention, it would be much moredifficult to manufacture the prior art switch. Also, this has thedisadvantage that the two movable contacts must always be electricallyconnected together and can not be insulated from each other. Theinductance and the stray capacitance of the contacts is much greaterthan that of the present invention so that such prior switch apparatusis not capable of as good a high frequency response. In addition, theswitch apparatus of the present invention has low contact resistance andlow open switch capacitance. As compared to previous switch apparatushaving cam actuated contacts mounted on one side of the circuit board,the present invention is more compact and requires less operating force,while at the same time, having a long useful lifetime and a relativelyinexpensive construction.

It is therefore one object of the present invention to provide animproved switch apparatus of compact and inexpensive construction havinglow inductance and capacitance so that it is capable of high frequencyresponse.

Another object is to provide such a switch apparatus in which themovable contacts are separately mounted by different mounting springsonopposite sides of a circuit board and are ganged together forsimultaneous movement of both of such contacts by means of a commonactuator.

sulator member joined to one movable contact.

An additional object of the present invention is to provide such aswitch apparatus in which the movable contacts are ganged together by aloose coupling means in the circuit board which enables relativemovement between the movable contacts.

Still another object of the invention is to provide such a switchapparatus in which the movable contacts are insulated from theirmounting springs by insulator members to provide the movable contactwith a low stray capacitance and a low inductance.

A still further object of the present invention is to provide such aswitch apparatus in which each movable contact acts as ashort-circuiting switch between two fixed contacts and is provided withtwo spaced leg portions through which current flows in oppositedirections to produce opposing fields which reduce the contactinductance. I

Other objects and advantages of the present invention will be apparentfrom the following detailed description of certain preferred embodimentsthereof and from the attached drawings of which:

FIG. 1' is a perspective plan view of one embodiment of the switchapparatus of the present invention with parts broken away for purposesof clarity;

FIG. 2 is an enlarged sectional view taken along the line 2-2 of FIG. 1.I

FIG. 3 is a sectional view of a portion of another embodiment of theswitch apparatus of the present invention employing a different type ofcam follower and coupling means;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 3.

DESCRIPTION OF PREFERRED EMBODIMENT As shown in FIGS. 1 and 2, oneembodiment of the switch apparatus of the present invention includes apair of movable switch contacts 10 and 12 joined through insulatormembers 14 and 16 to one end of leaf spring mounting members 18 and 20.The movable contacts are separately mounted on opposite sides of anetched circuit board 22 by attaching the other ends of mounting springs18 and 20 to the circuit board with a common rivet eyelet24 extendingthrough an aperture in such circuit board. The movable contacts 10 and12 are ganged together by a coupling member 26 of insulating materialextending through an opening 28 in the circuit board and looselycoupling the two insulator members 14 and 16. Thus, downward movement ofinsulator 14, to move contact 10 toward the circuit board, istransmitted through coupling member 26 to insulator 16 which movescontact 12 away from such circuit board. In the embodiment shown, oneend of the coupling member 26 is attached to the insulator 16,

such as by molding these members out of an integral piece of plasticmaterial. The other end of the coupling member is free to engage anddisengage the other'insulator 14 to enable relative movement between thecontacts l and 12 as shown in FIG. 2. A spacer portion 29 projects frominsulator 16 into contact with the circuit board 22 in the closedposition of movable contact 12 to set the proper amount of bending ofsuch contact.

As shown in FIG. 1, each of the movable contacts and 12 is provided witha pair of leg portions 30 and 32 which are spaced apart and extendsubstantially parallel from their free ends to their other ends joinedin common to the insulator 14 or 16. The leg portions 30 and 32 havebifurcated contacts at their free ends for engagement with two fixedcontacts 34 and 36, respectively, provided as spaced metal strips coatedon both sides of the circuit board 22. Thus, the movable contacts 10 and12 each short circuit the two fixed contacts 34 and 36 when such movablecontacts engage such fixed contacts. Current flows in oppositedirections through the leg portions 30 and 32 of the movable contact andproduce opposing magnetic fields which tend to cancel and, therefore,reduce the contact inductance. As shown in FIG. 2, the two pairs offixed contacts 34 and 36 on opposite sides of the circuit board aredisplaced with the upper pair being positioned to the left of the lowerpair to reduce the capacitance between such pairs of contacts.

The movable contacts 10 and 12 are insulated from their mounting springs18 and which lowers the stray capacitance between such movable contactsand the environment as well as reducing the inductance of such contacts.In addition, the open circuit capacitance between the movable contactsand the fixed contacts is also reduced because it is formed by twocapacitances connected in series. The result is a switch apparatus whichis capable of an extremely high frequency response, for example, up to 5gigahertz. This enables the switch to be employed to connect two 50 ohmcharacteristic impedance strip line type transmission lines togetherwhich may be formed by conductive strips on opposite sides of thecircuit board 22. In addition, the switch apparatus can also be used asa low impedance or high impedance attenuator switch with equally goodresults because it has a low stray capacitance providing a highimpedance in parallel with the attenuator elements.

A common actuating means, such as a rotary cam drum 38, is employed toactuate the switch apparatus of FIGS. 1 and 2 by engagement with a camfollower projection 40 on the insulator member 14. The cam drum 38 is ofa suitable plastic material and has cam projections 42 molded into itsouter surface. Such cam drum is rotated by a control shaft 44 connectedat one end to the cam drum and at its other end to a knob 46. Thecontrol shaft 44 and the cam drum 38 are mounted on the circuit board 22by a suitable mounting means 48 atthe opposite ends of such drum toprovide unitary switch apparatus. The mounting means 48 may be similarto that shown in co-pending U. S. application, Ser. No. 765,597, filedOct. 7, 1968, by Vollum et al., now U.S. Pat. No. 3,562,464.Alternatively, it is also possible to operate the cam follower 40 with asliding cam actuating means of the type shown in the abovementionedpatent. Of course, other actuating means can be employed including thoseof the electromechanical type such as a solenoid, with the plunger ofthe solenoid moving one of the insulator members 14 and 16 when the coilof such solenoid is energized.

Another embodiment of the present invention is shown in the FIGS. 3 and4 which is similar to that previously described except that it employs adifferent coupling member 50 and different movable contacts 52 and 54which are formed integral with their mounting springs out of a singlepiece of metal. As shown in FIG. 3, the coupling member 50 is providedwith a cam follower surface on an enlarged head portion 56 of conicalconfiguration at one end of such coupling member by molding it out of asuitable plastic material. The coupling member extends through a hole inthe mounting spring portion of the upper movable contact 52 and onthrough the opening 28 in the circuit board 22 so that its other endengages the lower movable contact 54 at its mounting spring portion.Rotation of the cam drum 38 brings a cam projection 42 into engagementwith the cam follower surface 56 and causes the coupling member 50 tomove downward. The coupling member 50 then closes movable contact 52after opening movable contact 54.

The movable contacts 52 and 54 each have spaced parallel leg portions30' and 32' which are similar to those of FIG. 1, but are notbifurcated. These leg portions 30 and 32' engage fixed contacts 34 and36 provided as metal strips coated on the surface of the circuit board22. These metal strips may be provided with gold plating in the contactareas since such strips are usually made of copper, in order to improvetheir electrical characteristics. It should also be noted that while themovable contacts 52 and 54, and their spring mounting portions areelectrically connected together and not insulated from each other likethe embodiment of FIG. 1, the two movable contacts may be insulated fromeach other by fastening the leaf springs with separate solderconnections rather than the common rivet 24 of FIG. 1. Thus, while themovable contacts are shown as shorting switches for interconnecting thetwo fixed contacts 34 and 36 as shown in FIG. 4, they may also be usedto electrically connect a single fixed contact to a terminal stripconnect to,the fixed end of the leaf spring. Again, it should be notedthat another common actuator, such as a sliding cam actuator mechanism,can be employed rather than the rotary cam drum 38.

It will be obvious to those having ordinary skill in the art that manychanges may be made in the details of the above-described preferredembodiments of the present invention without departing from the spiritof the invention. Therefore, the scope of the present invention shouldonly be determined by the following claims.

We claim:

1. Switch apparatus comprising:

a support plate of insulating material;

a pairof fixed switch contacts attached to the opposite sides of saidsupport plate;

a pair of movable switch contacts mounted by two separate resilientmounting means on said opposite sides of said support plate for movementbetween a closed position engaging said fixed contacts and an openposition spaced from said fixed contacts, said movable contacts beingeach attached to said resilient mounting means through an insulatormember, and;

common actuator means for moving both of said movable contacts towardand away from said support plate between said open and closed positions,

including a movable coupling member extending through an opening in saidsupport plate to couple said movable contacts together and operate themas ganged contacts.

2 Switch apparatus in accordance with claim 1 in which the couplingmember loosely couples the movable contacts for movement together whileenabling relative movement between said movable contacts.

3. Switch apparatus in accordance with claim 1 in which the supportplate is a circuit board with the fixed contacts being metal layers onsaid circuit board and the actuator means is a cam actuator means.

4. Switch apparatus in accordance with claim 3 in which .the camactuator means includes a rotary cam member. mounted on the circuitboard and the two mounting means are spring members attached to oppositesides of the circuit board.

5. Switch apparatus in accordance with claim 4 in which the cam actuatormeans includes a cam follower of plastic insulating material which movesat least one of the movable contacts between said open and closedpositions when said cam follower is engaged by said cam member.

6. Switch apparatus in accordance with claim 5 in which the cam followeris provided as a cam engaging portion on one of a pair of insulatormembers connecting each of said movable contacts to one end of a leafspring mounting member having its other end attached to the circuitboard.

7. Switch apparatus in accordance with claim 6 in which the otherinsulator member is provided with a spacer portion projecting toward thecircuit board which engages the circuit board in the closed position ofthe movable contact connected to said other insulator member to set theamount of bending of such movable contact in said closed position.

8. Switch apparatus comprising:

a support plate of insulating material;

a pair of fixed switch contacts attached to the opposite sides of saidsupport plate;

a pair of movable switch contacts mounted by two separate mounting meanson said opposite sides of a said support plate for movement between aclosed position engaging said fixed contacts and an open position spacedfrom said fixed contacts;

common actuator means including a movable cam member for moving both ofsaid movable contacts toward andaway from said support plate betweensaid open and closed positions;

said actuator means also including a movable coupling member with a camfollower portion engagedby said cam member extending through an openingin said support plate to couple said movable contacts together andoperate them as ganged contacts.

9. Switch apparatus in'accordance with claim 8 in which the couplingmember loosely couples the movable contacts for; movement together whileenabling relative movement between said movable contacts.

10. Switch apparatus in accordance with claim 8 in which the supportplate is a circuit board with the fixed contacts being metal layers onsaid circuit board and the actuator means is a cam actuator means.

11. Switch apparatus in accordance with claim 10 in which the camactuator means includes a rotary cam member mounted on the circuit boardand the two mounting means are resilient members attached to oppositesides of the circuit board.

12. Switch apparatus in accordance with claim 11 in which the camactuator means includes a cam follower of plastic insulating materialwhich moves at least one of the movable contacts between said open andclosed positions when said cam follower is engaged by said cam member.

13. Switch apparatus in accordance with claim 12 in which the movablecontacts have spring mounting portions attached to said circuit board,and the cam follower is provided as a cam engaging portion of one end ofsaid coupling member, said coupling member extending through a hole inone of said spring portions and engaging the other of said springportions with its larged head portion having the cam follower portionthereon.

15. Switch apparatus comprising:

a support plate of insulating material;

a plurality of spaced fixed switch contact means on said support plate;

a plurality of movable switch contact means mounted by resilientmounting means on said support plate for movement between a closedposition engaging said fixed switch contact means and an open positionspaced from said fixed switch contact means, said movable switch contactmeans being connected to said resilient mounting means throughinsulation means and said insulation means including means to couplesaid movable switch contact means together; and

common actuator means for moving said plurality of movable switchcontact means toward and away from said support plate between said openand closed positions including actuator-engaging means provided by saidinsulation means for engagement by said common actuator means to operatesaid plurality of movable switch contact means as ganged switch contactmeans.

16. Switch apparatus comprising! a support plate of insulating material;

a plurality of spaced fixed switch contact means on said support plate;v

a plurality of movable switch means including resilient mounting meansmounting said movable switch means on said support plate and movableswitch contact means for movement between a closed position engagingsaid fixed switch contact means and an open position spaced from saidfixed switch contact means;

insulation means extending between said plurality of movable switchmeans for coupling (connecting) said movable switch means together; and

common actuator means for moving said plurality of movable switch meanstoward and away from said support plate between said open and closedpositions including actuator-engaging means provided by said insulationmeans for engagement by said common actuator means to operate saidplurality V nected to said insulation means and another end definingcontact-engaging means for engagement with said fixed switch contactmeans, said insulation means insulating said resilient mounting meansfrom said contact element means; and

actuator means for moving said movable switch contact means toward andaway from said support plate between open and closed contact positionsincluding actuator-engaging means provided by said insulation means forengagement by said actuator means to operate said movable switch contactmeans between said open and closed positions.

1. Switch apparatus comprising: a support plate of insulating material;a pair of fixed switch contacts attached to the opposite sides of saidsupport plate; a pair of movable switch contacts mounted by two separateresilient mounting means on said opposite sides of said support platefor movement between a closed position engaging said fixed contacts andan open position spaced from said fixed contacts, said movable contactsbeing each attached to said resilient mounting means through aninsulator member, and; common actuator means for moving both of saidmovable contacts toward and away from said support plate between saidopen and closed positions, including a movable coupling member extendingthrough an opening in said support plate to couple said movable contactstogether and operate them as ganged contacts.
 1. Switch apparatuscomprising: a support plate of insulating material; a pair of fixedswitch contacts attached to the opposite sides of said support plate; apair of movable switch contacts mounted by two separate resilientmounting means on said opposite sides of said support plate for movementbetween a closed position engaging said fixed contacts and an openposition spaced from said fixed contacts, said movable contacts beingeach attached to said resilient mounting means through an insulatormember, and; common actuator means for moving both of said movablecontacts toward and away from said support plate between said open andclosed positions, including a movable coupling member extending throughan opening in said support plate to couple said movable contactstogether and operate them as ganged contacts.
 2. Switch apparatus inaccordance with claim 1 in which the coupling member loosely couples themovable contacts for movement together while enabling relative movementbetween said movable contacts.
 3. Switch apparatus in accordance withclaim 1 in which the support plate is a circuit board with the fixedcontacts being metal layers on said circuit board and the actuator meansis a cam actuator means.
 4. Switch apparatus in accordance with claim 3in which the cam actuator means includes a rotary cam member mounted onthe circuit board and the two mounting means are spring members attachedto opposite sides of the circuit board.
 5. Switch apparatus inaccordance with claim 4 in which the cam actuator means includes a camfollower of plastic insulating material which moves at least one of themovable contacts between said opeN and closed positions when said camfollower is engaged by said cam member.
 6. Switch apparatus inaccordance with claim 5 in which the cam follower is provided as a camengaging portion on one of a pair of insulator members connecting eachof said movable contacts to one end of a leaf spring mounting memberhaving its other end attached to the circuit board.
 7. Switch apparatusin accordance with claim 6 in which the other insulator member isprovided with a spacer portion projecting toward the circuit board whichengages the circuit board in the closed position of the movable contactconnected to said other insulator member to set the amount of bending ofsuch movable contact in said closed position.
 8. Switch apparatuscomprising: a support plate of insulating material; a pair of fixedswitch contacts attached to the opposite sides of said support plate; apair of movable switch contacts mounted by two separate mounting meanson said opposite sides of said support plate for movement between aclosed position engaging said fixed contacts and an open position spacedfrom said fixed contacts; common actuator means including a movable cammember for moving both of said movable contacts toward and away fromsaid support plate between said open and closed positions; said actuatormeans also including a movable coupling member with a cam followerportion engaged by said cam member extending through an opening in saidsupport plate to couple said movable contacts together and operate themas ganged contacts.
 9. Switch apparatus in accordance with claim 8 inwhich the coupling member loosely couples the movable contacts formovement together while enabling relative movement between said movablecontacts.
 10. Switch apparatus in accordance with claim 8 in which thesupport plate is a circuit board with the fixed contacts being metallayers on said circuit board and the actuator means is a cam actuatormeans.
 11. Switch apparatus in accordance with claim 10 in which the camactuator means includes a rotary cam member mounted on the circuit boardand the two mounting means are resilient members attached to oppositesides of the circuit board.
 12. Switch apparatus in accordance withclaim 11 in which the cam actuator means includes a cam follower ofplastic insulating material which moves at least one of the movablecontacts between said open and closed positions when said cam followeris engaged by said cam member.
 13. Switch apparatus in accordance withclaim 12 in which the movable contacts have spring mounting portionsattached to said circuit board, and the cam follower is provided as acam engaging portion of one end of said coupling member, said couplingmember extending through a hole in one of said spring portions andengaging the other of said spring portions with its other end. 14.Switch apparatus in accordance with claim 8 in which the coupling memberis of insulating material and extends through a hole in a supportportion of one of the movable contacts so that an enlarged head portionat one end of said coupling member engages said one movable contact andthe other end of said coupling member engages the other movable contact,said enlarged head portion having the cam follower portion thereon. 15.Switch apparatus comprising: a support plate of insulating material; aplurality of spaced fixed switch contact means on said support plate; aplurality of movable switch contact means mounted by resilient mountingmeans on said support plate for movement between a closed positionengaging said fixed switch contact means and an open position spacedfrom said fixed switch contact means, said movable switch contact meansbeing connected to said resilient mounting means through insulationmeans and said insulation means including means to couple said movableswitch contact means together; and common actuator means for moving saidplurality of movable switch contact means toward and away from saidsUpport plate between said open and closed positions includingactuator-engaging means provided by said insulation means for engagementby said common actuator means to operate said plurality of movableswitch contact means as ganged switch contact means.
 16. Switchapparatus comprising: a support plate of insulating material; aplurality of spaced fixed switch contact means on said support plate; aplurality of movable switch means including resilient mounting meansmounting said movable switch means on said support plate and movableswitch contact means for movement between a closed position engagingsaid fixed switch contact means and an open position spaced from saidfixed switch contact means; insulation means extending between saidplurality of movable switch means for coupling (connecting) said movableswitch means together; and common actuator means for moving saidplurality of movable switch means toward and away from said supportplate between said open and closed positions including actuator-engagingmeans provided by said insulation means for engagement by said commonactuator means to operate said plurality of movable switch means asganged switch contact means.